Machine for drying photographic prints



Dec. 31, 1929. J. w. ROBINSON MACHINE FOR DRYING PHOTOGRAPHIC PRINTS Filed July 5, L928 l o o v Inventor James W Rabmson Attorney Patented Dec. 31, 1929 UNITED STATES JAMES w. nonmsou,

mnosn A. may m1: nocnnsrnn, new Tom:

01 ROCHESTER, NEW YORK,

PATENT, OFFICE ASSIGNOB OF ONE-FOURTH TO ONE-FOURTH TO RICHARD WALTER WHITE, BOTH OF Application filed July 5, 1928. Serial No. 290,307.

The object of this invention is to provide a newand improved apparatus or machme for drying photographic prints.

Another object of the invention is to make the apparatus very compact and thus secure a saving in floor space.

These and other objects of the invention will be illustrated in the drawing, described in the specification and pointed out 1n the claims at the end thereof.

In the drawings:

Figure 1 is a perspective View of the machine with the near end frame and gearing of the machine cut away on a section to expose the inside of the machine, the section being taken on the line 1"1 of Figure 3.

Figure 2 is a side elevation of the machine with the end frame of the machine partly broken away to expose the gearing.

Figure 3' is a top plan view of the belt with the canvas layer broken away to expose the metal layer and the perforations therein.

In the drawings like reference numerals indicate like parts.

It is well known that photographic prints are developed in and fixed in a liquid bath and various machines have been contrived for the purpose of drying such prints quickly. Such machines that have heretofore been used are very large and take an unnecessary amount of floor space to secure the length of travel of the belts that is needed to secure proper drying of the prints. I have overcome these objections in the machine that will now be described.

In the drawing reference numeral 1 indicates the frame on the far end of the machine and reference numeral 2 indicates the frame on the near end of the machine. These frames are tied together with four tie rods 3, 4, 5 and 6. In these frames are journaled the rollers 7, 8, chine and the rollers 11, 12, 13, 14 and 15 at the front of the machine. Over these rollers pass two endless belts 16 and 16A each of which is made up of two layers, one of which is made of thin sheet metal 17 and the other is made of canvas 18 which layers are sewed together in seams 19 and 20. The 50 metal belt is made preferably of brass or 9 and 10 at the rear of the ma-.

copper and is about .005" more or less in thickness. The belt 16-A passes over the roller in the following order, namely 11, 8, 13, 9, 15, 10 and 7. The other belt 16 passes over rollers in the following order 12, 8, 13, 9 and 14. All of these rollers are driven by the gear wheels shown at the right hand end of Figure 2 which gear Wheels are numbered 25, 26, 27, 28 and 29. The gear wheel 26 is an idler and is in no way connected to the roller 12, the roller 12 being driven by the friction of the belt 16 thereon. The roller 12 is set forward of the vertical line that passes through the axes of'the rollers 11, 13, 14 and 15 so as to extend the belt 16 and provide a shelf 30 on which the prints can be laid before they start through the machine.

The metal belt 17 is perforated with a large number of holes. It will be understood that the belt on one sample machine will be for-7o example about 18" wide and the perforations will be arranged in rows that contain 14 or 15 holes in each row. Each perforation will be about in diameter and the perforations in one row will be staggered with respect to the perforations in the other row. This will provide about as much area in the holes as is left in the metal belt and will provide amply for ventilation and evaporatron.

It will be seen that the belts come together under the roller 11 and the belts separate from each other under the roll 14 and the print is carried between the belts through the serpentine path that passes backward and forward through the machine twice each way, the print being started wet at the top of the machine and being discharged dry at the bottom of the machine. i

Each horizontal run of the belt passes between two heating units 35 and 36 which heating units are alike and are-made up of aluminum plates each of which on the side next to the belt carries electrical resistance heating elements 31 and 32. The aluminum plates are recessed to receive the heating elements so that the heating elements do not come in contact with the belts the belts only coming in contact with the aluminum plates which prese t a smooth surface thereto. The 100 i5 so that the tension on the way.

heat generated by the electrical resistance elements is communicated directly to the belts or is absorbed by the aluminum plates and is distributed by them over the belts so that the belts are subjected to a large area of heating surface, as they go back andforth through the machine. The belt is uncovered so to speak a t'ter leaving each pair of heating plates and bet ore it comes into contact with the next pair of heating plates so that ample opportunity for evaporation and drying of the belts and the photographic print is secured.

The rollers 8 and 9 are mounted on hearing blocks 40 and 41 which are adapted to slide in the frames so as to take up the slack of the belt. To put the belt under proper tension, I provide tension springs 42, 42 which are attached to the bearing blocks 40 and 41 at one end and to adjusting the screws 43 and 44 at the other end. By turning the screws the bearing blocks are drawn to the left in Figure 2 and the belts are put under proper tension. The roller 12 is independently adjustable by means of the set screw one belt can be adjusted to the tension on the other.

The power can be applied to any of the shafts carrying gear wheels in any suitable The electrical heating elements will be connected up in series or series parallel as may be desired with the source of current. A rheostat 46 is tensity of the heating. The belts will be driven at a speedsufiicient to carry the prints through the machine in about 2 minutes and the heating effect will be adjusted to secure drying in this time.

. If the canvas belt were used without the metal backing the wetting and drying to which the belt is subjected would cause it to wrinkle so that it would not run straight and it would wrinkle and spoil'the prints. The metal backing holds the canvas smooth at all times and the holes in the metal backing allow the moisture from the print and the canvas belt to escape. If there were no holes the moisture could not escape and the print would come through nearly as wet as when fed into the machine. The double belt makes it possible to not only dry the prints that have emulsion on one side but prints that have emulsion on both sides as well. claim: 1. The combination in a machine for drying photographic prints of a pair of endless belts, two series of rollers over which said belts pass in a serpentine path, the belts being arranged in parallel planes one above another, several rollers being in common to both series and causing the belts to travel together, said belts being each made up of a layer of canvas and a layer of metal fastened together, said metal belt having a large number of perforations therein to provide for ventilation, the canvas layers provided to regulate the in-' coming together between the metal layers and being adapted to bet-Ween them.

2. The combination in a machine for drying photographic prints of a pairof endless belts, two series of rollers over which said belts pass in a serpentine )ath, said belts being each made up of a layer of canvas and a layer of metal fastened together, heating units placed above and below the belts where they travel together in each plane and close to the belts so as to heat the belts and cause the drying of the prints, the canvas layers coming together and being adapted to hold the photographs between them, the metal layers traveling between the heating units and the canvas layers.

3. The combination in a machine for drying photographic prints of a pair of endless belts, two series of rollers over which said belts pass in a serpentine path, said belts being each made up of a layer of canvas and a layer of metal fastened together, heating units placed above and below the belts where they travel together in each plane and close to the belts so as to heat the belts and cause the drying of the prints, each of said heating units comprising a metal plate, said plate being recessed on the side exposed to the belt, an electrical resistance-element placed in said recess the canvas layers coming together and being adapted to hold the photographs between them, the metal layers traveling between the heating units and the canvas layers.

, 4. A belt for a drying apparatus having a layer of canvas and a layer of metal fastened together, said layer of metal having a large number of perforations therein to provide for the ventilation of the layer of canvas.

In testimony whereof I am); my signature.

JAMES W. ROBINSON.

hold the photographs 

